Cold metal transfer cycle step braze welding process was modified to successfully produce an aluminum alloy/Zn-coated steel linear joint with a closed square butt joint configuration. The braze-welded joint shows wide-spreading and low wetting angle of molten filler alloy on both sides of the steel. The butt joint is formed by the overlapping of individual spot braze welds during cold metal transfer cycle step braze welding. The microstructure at the front, backside, and face side interface of the Al/steel joint were characterized in terms of the crystal structure, morphology, and thickness of intermetallic compounds by scanning electron microscopy, analytical transmission electron microscopy, and energy dispersive X-ray spectroscopy. The interfacial structure of Al/τ_5(H)-Al₈Fe₂Si(film-like)/θ-Al₃Fe(rod-like)/θ-Al₃Fe(500 nm)/η-Al₅Fe₂(2.5 µm)/Fe is formed at the front interface associated with high-temperature interaction between liquid Al alloy and Zn-coated steel. On the contrary, Al/τ_5(C)-Al₈(Fe,Mn)₂Si/τ_5(H)-Al₈Fe₂Si/θ-Al₃Fe(1.2 µm)/η-Al₅Fe₂(500 nm)/Fe is present at the backside interface associated with relatively low-temperature interaction between liquid Al alloy and Zn-coated steel. The intermetallic compounds and morphology at the face interface associated with medium temperature interaction are similar to those at the backside interface. However, the thickness of the η-Al₅Fe₂ layer is only 220 nm, which is caused as a result of the interaction of molten Al filler alloy with the bare steel sheared surface without Zn coating. The mechanism for the formation of varied intermetallic compounds at the different interfaces is discussed.

修改了冷金属转移循环步骤钎焊工艺，以成功生产出具有封闭方形对接接头配置的铝合金/镀锌钢线性接头。钎焊接头在钢的两侧均显示出熔融填充合金的广泛分布和低润湿角。对接接头是在冷金属转移循环步骤铜焊过程中各个点焊的交叠处形成的。通过扫描电子显微镜，分析型透射电子显微镜和能量色散X射线对Al /钢接头的正面，背面和正面接口的微观结构进行了表征，包括金属间化合物的晶体结构，形态和厚度光谱学。Al / τ5 _（H） -Al ₈的界面结构的Fe ₂的Si（薄膜状）/ θ -Al ₃的Fe（棒状）/ θ -Al ₃的Fe（500纳米）/ η -Al ₅的Fe ₂（2.5  μ M）在前面界面形成/ Fe的相关联在液态铝合金和镀锌钢之间具有高温相互作用。相反，铝/ τ _5（C） -Al ₈（铁，锰）₂的Si / τ _5（H） -Al ₈的Fe ₂的Si / θ -Al ₃的Fe（1.2  μ M）/ η -Al ₅的Fe ₂（500 nm）/ Fe存在于背面界面，与液态铝合金和镀锌钢之间的相对低温相互作用有关。与中等温度相互作用有关的面界面处的金属间化合物和形态与背面界面处的相似。然而，η- Al ₅ Fe ₂层的厚度仅为220nm，这是由于熔融的Al填充合金与没有Zn涂层的裸钢剪切表面的相互作用导致的。讨论了在不同界面形成各种金属间化合物的机理。